1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * LTRF216A Ambient Light Sensor
4 *
5 * Copyright (C) 2022 Collabora, Ltd.
6 * Author: Shreeya Patel <shreeya.patel@collabora.com>
7 *
8 * Copyright (C) 2021 Lite-On Technology Corp (Singapore)
9 * Author: Shi Zhigang <Zhigang.Shi@liteon.com>
10 *
11 * IIO driver for LTRF216A (7-bit I2C slave address 0x53).
12 */
13
14 #include <linux/bitfield.h>
15 #include <linux/bits.h>
16 #include <linux/delay.h>
17 #include <linux/i2c.h>
18 #include <linux/init.h>
19 #include <linux/iopoll.h>
20 #include <linux/mod_devicetable.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/pm.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/regmap.h>
26
27 #include <linux/iio/iio.h>
28
29 #include <linux/unaligned.h>
30
31 #define LTRF216A_ALS_RESET_MASK BIT(4)
32 #define LTRF216A_ALS_DATA_STATUS BIT(3)
33 #define LTRF216A_ALS_ENABLE_MASK BIT(1)
34 #define LTRF216A_MAIN_CTRL 0x00
35 #define LTRF216A_ALS_MEAS_RES 0x04
36 #define LTRF216A_ALS_GAIN 0x05
37 #define LTRF216A_PART_ID 0x06
38 #define LTRF216A_MAIN_STATUS 0x07
39 #define LTRF216A_ALS_CLEAR_DATA_0 0x0a
40 #define LTRF216A_ALS_CLEAR_DATA_1 0x0b
41 #define LTRF216A_ALS_CLEAR_DATA_2 0x0c
42 #define LTRF216A_ALS_DATA_0 0x0d
43 #define LTRF216A_ALS_DATA_1 0x0e
44 #define LTRF216A_ALS_DATA_2 0x0f
45 #define LTRF216A_INT_CFG 0x19
46 #define LTRF216A_INT_PST 0x1a
47 #define LTRF216A_ALS_THRES_UP_0 0x21
48 #define LTRF216A_ALS_THRES_UP_1 0x22
49 #define LTRF216A_ALS_THRES_UP_2 0x23
50 #define LTRF216A_ALS_THRES_LOW_0 0x24
51 #define LTRF216A_ALS_THRES_LOW_1 0x25
52 #define LTRF216A_ALS_THRES_LOW_2 0x26
53 #define LTRF216A_ALS_READ_DATA_DELAY_US 20000
54
55 static const int ltrf216a_int_time_available[][2] = {
56 { 0, 400000 },
57 { 0, 200000 },
58 { 0, 100000 },
59 { 0, 50000 },
60 { 0, 25000 },
61 };
62
63 static const int ltrf216a_int_time_reg[][2] = {
64 { 400, 0x03 },
65 { 200, 0x13 },
66 { 100, 0x22 },
67 { 50, 0x31 },
68 { 25, 0x40 },
69 };
70
71 struct ltr_chip_info {
72 /* Chip contains CLEAR_DATA_0/1/2 registers at offset 0xa..0xc */
73 bool has_clear_data;
74 /* Lux calculation multiplier for ALS data */
75 int lux_multiplier;
76 };
77
78 /*
79 * Window Factor is needed when the device is under Window glass
80 * with coated tinted ink. This is to compensate for the light loss
81 * due to the lower transmission rate of the window glass and helps
82 * in calculating lux.
83 */
84 #define LTRF216A_WIN_FAC 1
85
86 struct ltrf216a_data {
87 struct regmap *regmap;
88 struct i2c_client *client;
89 const struct ltr_chip_info *info;
90 u32 int_time;
91 u16 int_time_fac;
92 u8 als_gain_fac;
93 /*
94 * Protects regmap accesses and makes sure integration time
95 * remains constant during the measurement of lux.
96 */
97 struct mutex lock;
98 };
99
100 static const struct iio_chan_spec ltrf216a_channels[] = {
101 {
102 .type = IIO_LIGHT,
103 .info_mask_separate =
104 BIT(IIO_CHAN_INFO_RAW) |
105 BIT(IIO_CHAN_INFO_PROCESSED) |
106 BIT(IIO_CHAN_INFO_INT_TIME),
107 .info_mask_separate_available =
108 BIT(IIO_CHAN_INFO_INT_TIME),
109 },
110 };
111
ltrf216a_reset(struct iio_dev * indio_dev)112 static void ltrf216a_reset(struct iio_dev *indio_dev)
113 {
114 struct ltrf216a_data *data = iio_priv(indio_dev);
115
116 /* reset sensor, chip fails to respond to this, so ignore any errors */
117 regmap_write(data->regmap, LTRF216A_MAIN_CTRL, LTRF216A_ALS_RESET_MASK);
118
119 /* reset time */
120 usleep_range(1000, 2000);
121 }
122
ltrf216a_enable(struct iio_dev * indio_dev)123 static int ltrf216a_enable(struct iio_dev *indio_dev)
124 {
125 struct ltrf216a_data *data = iio_priv(indio_dev);
126 struct device *dev = &data->client->dev;
127 int ret;
128
129 /* enable sensor */
130 ret = regmap_set_bits(data->regmap,
131 LTRF216A_MAIN_CTRL, LTRF216A_ALS_ENABLE_MASK);
132 if (ret) {
133 dev_err(dev, "failed to enable sensor: %d\n", ret);
134 return ret;
135 }
136
137 /* sleep for one integration cycle after enabling the device */
138 msleep(ltrf216a_int_time_reg[0][0]);
139
140 return 0;
141 }
142
ltrf216a_disable(struct iio_dev * indio_dev)143 static int ltrf216a_disable(struct iio_dev *indio_dev)
144 {
145 struct ltrf216a_data *data = iio_priv(indio_dev);
146 struct device *dev = &data->client->dev;
147 int ret;
148
149 ret = regmap_write(data->regmap, LTRF216A_MAIN_CTRL, 0);
150 if (ret)
151 dev_err(dev, "failed to disable sensor: %d\n", ret);
152
153 return ret;
154 }
155
ltrf216a_cleanup(void * data)156 static void ltrf216a_cleanup(void *data)
157 {
158 struct iio_dev *indio_dev = data;
159
160 ltrf216a_disable(indio_dev);
161 }
162
ltrf216a_set_int_time(struct ltrf216a_data * data,int itime)163 static int ltrf216a_set_int_time(struct ltrf216a_data *data, int itime)
164 {
165 struct device *dev = &data->client->dev;
166 unsigned int i;
167 u8 reg_val;
168 int ret;
169
170 for (i = 0; i < ARRAY_SIZE(ltrf216a_int_time_available); i++) {
171 if (ltrf216a_int_time_available[i][1] == itime)
172 break;
173 }
174 if (i == ARRAY_SIZE(ltrf216a_int_time_available))
175 return -EINVAL;
176
177 reg_val = ltrf216a_int_time_reg[i][1];
178
179 ret = regmap_write(data->regmap, LTRF216A_ALS_MEAS_RES, reg_val);
180 if (ret) {
181 dev_err(dev, "failed to set integration time: %d\n", ret);
182 return ret;
183 }
184
185 data->int_time_fac = ltrf216a_int_time_reg[i][0];
186 data->int_time = itime;
187
188 return 0;
189 }
190
ltrf216a_get_int_time(struct ltrf216a_data * data,int * val,int * val2)191 static int ltrf216a_get_int_time(struct ltrf216a_data *data,
192 int *val, int *val2)
193 {
194 *val = 0;
195 *val2 = data->int_time;
196 return IIO_VAL_INT_PLUS_MICRO;
197 }
198
ltrf216a_set_power_state(struct ltrf216a_data * data,bool on)199 static int ltrf216a_set_power_state(struct ltrf216a_data *data, bool on)
200 {
201 struct device *dev = &data->client->dev;
202 int ret = 0;
203
204 if (on) {
205 ret = pm_runtime_resume_and_get(dev);
206 if (ret) {
207 dev_err(dev, "failed to resume runtime PM: %d\n", ret);
208 return ret;
209 }
210 } else {
211 pm_runtime_mark_last_busy(dev);
212 pm_runtime_put_autosuspend(dev);
213 }
214
215 return ret;
216 }
217
ltrf216a_read_data(struct ltrf216a_data * data,u8 addr)218 static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
219 {
220 struct device *dev = &data->client->dev;
221 int ret, val;
222 u8 buf[3];
223
224 ret = regmap_read_poll_timeout(data->regmap, LTRF216A_MAIN_STATUS,
225 val, val & LTRF216A_ALS_DATA_STATUS,
226 LTRF216A_ALS_READ_DATA_DELAY_US,
227 LTRF216A_ALS_READ_DATA_DELAY_US * 50);
228 if (ret) {
229 dev_err(dev, "failed to wait for measurement data: %d\n", ret);
230 return ret;
231 }
232
233 ret = regmap_bulk_read(data->regmap, addr, buf, sizeof(buf));
234 if (ret) {
235 dev_err(dev, "failed to read measurement data: %d\n", ret);
236 return ret;
237 }
238
239 return get_unaligned_le24(&buf[0]);
240 }
241
ltrf216a_get_lux(struct ltrf216a_data * data)242 static int ltrf216a_get_lux(struct ltrf216a_data *data)
243 {
244 int ret, greendata;
245 u64 lux;
246
247 ret = ltrf216a_set_power_state(data, true);
248 if (ret)
249 return ret;
250
251 greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
252 if (greendata < 0)
253 return greendata;
254
255 ltrf216a_set_power_state(data, false);
256
257 lux = greendata * data->info->lux_multiplier * LTRF216A_WIN_FAC;
258
259 return lux;
260 }
261
ltrf216a_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)262 static int ltrf216a_read_raw(struct iio_dev *indio_dev,
263 struct iio_chan_spec const *chan, int *val,
264 int *val2, long mask)
265 {
266 struct ltrf216a_data *data = iio_priv(indio_dev);
267 int ret;
268
269 switch (mask) {
270 case IIO_CHAN_INFO_RAW:
271 ret = ltrf216a_set_power_state(data, true);
272 if (ret)
273 return ret;
274 mutex_lock(&data->lock);
275 ret = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
276 mutex_unlock(&data->lock);
277 ltrf216a_set_power_state(data, false);
278 if (ret < 0)
279 return ret;
280 *val = ret;
281 return IIO_VAL_INT;
282 case IIO_CHAN_INFO_PROCESSED:
283 mutex_lock(&data->lock);
284 ret = ltrf216a_get_lux(data);
285 mutex_unlock(&data->lock);
286 if (ret < 0)
287 return ret;
288 *val = ret;
289 *val2 = data->als_gain_fac * data->int_time_fac;
290 return IIO_VAL_FRACTIONAL;
291 case IIO_CHAN_INFO_INT_TIME:
292 mutex_lock(&data->lock);
293 ret = ltrf216a_get_int_time(data, val, val2);
294 mutex_unlock(&data->lock);
295 return ret;
296 default:
297 return -EINVAL;
298 }
299 }
300
ltrf216a_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)301 static int ltrf216a_write_raw(struct iio_dev *indio_dev,
302 struct iio_chan_spec const *chan, int val,
303 int val2, long mask)
304 {
305 struct ltrf216a_data *data = iio_priv(indio_dev);
306 int ret;
307
308 switch (mask) {
309 case IIO_CHAN_INFO_INT_TIME:
310 if (val != 0)
311 return -EINVAL;
312 mutex_lock(&data->lock);
313 ret = ltrf216a_set_int_time(data, val2);
314 mutex_unlock(&data->lock);
315 return ret;
316 default:
317 return -EINVAL;
318 }
319 }
320
ltrf216a_read_available(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)321 static int ltrf216a_read_available(struct iio_dev *indio_dev,
322 struct iio_chan_spec const *chan,
323 const int **vals, int *type, int *length,
324 long mask)
325 {
326 switch (mask) {
327 case IIO_CHAN_INFO_INT_TIME:
328 *length = ARRAY_SIZE(ltrf216a_int_time_available) * 2;
329 *vals = (const int *)ltrf216a_int_time_available;
330 *type = IIO_VAL_INT_PLUS_MICRO;
331 return IIO_AVAIL_LIST;
332 default:
333 return -EINVAL;
334 }
335 }
336
337 static const struct iio_info ltrf216a_info = {
338 .read_raw = ltrf216a_read_raw,
339 .write_raw = ltrf216a_write_raw,
340 .read_avail = ltrf216a_read_available,
341 };
342
ltrf216a_readable_reg(struct device * dev,unsigned int reg)343 static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
344 {
345 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
346 struct ltrf216a_data *data = iio_priv(indio_dev);
347
348 switch (reg) {
349 case LTRF216A_MAIN_CTRL:
350 case LTRF216A_ALS_MEAS_RES:
351 case LTRF216A_ALS_GAIN:
352 case LTRF216A_PART_ID:
353 case LTRF216A_MAIN_STATUS:
354 case LTRF216A_ALS_DATA_0:
355 case LTRF216A_ALS_DATA_1:
356 case LTRF216A_ALS_DATA_2:
357 case LTRF216A_INT_CFG:
358 case LTRF216A_INT_PST:
359 case LTRF216A_ALS_THRES_UP_0:
360 case LTRF216A_ALS_THRES_UP_1:
361 case LTRF216A_ALS_THRES_UP_2:
362 case LTRF216A_ALS_THRES_LOW_0:
363 case LTRF216A_ALS_THRES_LOW_1:
364 case LTRF216A_ALS_THRES_LOW_2:
365 return true;
366 case LTRF216A_ALS_CLEAR_DATA_0:
367 case LTRF216A_ALS_CLEAR_DATA_1:
368 case LTRF216A_ALS_CLEAR_DATA_2:
369 return data->info->has_clear_data;
370 default:
371 return false;
372 }
373 }
374
ltrf216a_writable_reg(struct device * dev,unsigned int reg)375 static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
376 {
377 switch (reg) {
378 case LTRF216A_MAIN_CTRL:
379 case LTRF216A_ALS_MEAS_RES:
380 case LTRF216A_ALS_GAIN:
381 case LTRF216A_INT_CFG:
382 case LTRF216A_INT_PST:
383 case LTRF216A_ALS_THRES_UP_0:
384 case LTRF216A_ALS_THRES_UP_1:
385 case LTRF216A_ALS_THRES_UP_2:
386 case LTRF216A_ALS_THRES_LOW_0:
387 case LTRF216A_ALS_THRES_LOW_1:
388 case LTRF216A_ALS_THRES_LOW_2:
389 return true;
390 default:
391 return false;
392 }
393 }
394
ltrf216a_volatile_reg(struct device * dev,unsigned int reg)395 static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
396 {
397 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
398 struct ltrf216a_data *data = iio_priv(indio_dev);
399
400 switch (reg) {
401 case LTRF216A_MAIN_STATUS:
402 case LTRF216A_ALS_DATA_0:
403 case LTRF216A_ALS_DATA_1:
404 case LTRF216A_ALS_DATA_2:
405 return true;
406 /*
407 * If these registers are not present on a chip (like LTR-308),
408 * the missing registers are not considered volatile.
409 */
410 case LTRF216A_ALS_CLEAR_DATA_0:
411 case LTRF216A_ALS_CLEAR_DATA_1:
412 case LTRF216A_ALS_CLEAR_DATA_2:
413 return data->info->has_clear_data;
414 default:
415 return false;
416 }
417 }
418
ltrf216a_precious_reg(struct device * dev,unsigned int reg)419 static bool ltrf216a_precious_reg(struct device *dev, unsigned int reg)
420 {
421 return reg == LTRF216A_MAIN_STATUS;
422 }
423
424 static const struct regmap_config ltrf216a_regmap_config = {
425 .name = "ltrf216a",
426 .reg_bits = 8,
427 .val_bits = 8,
428 .cache_type = REGCACHE_RBTREE,
429 .max_register = LTRF216A_ALS_THRES_LOW_2,
430 .readable_reg = ltrf216a_readable_reg,
431 .writeable_reg = ltrf216a_writable_reg,
432 .volatile_reg = ltrf216a_volatile_reg,
433 .precious_reg = ltrf216a_precious_reg,
434 .disable_locking = true,
435 };
436
ltrf216a_probe(struct i2c_client * client)437 static int ltrf216a_probe(struct i2c_client *client)
438 {
439 struct ltrf216a_data *data;
440 struct iio_dev *indio_dev;
441 int ret;
442
443 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
444 if (!indio_dev)
445 return -ENOMEM;
446
447 data = iio_priv(indio_dev);
448
449 data->regmap = devm_regmap_init_i2c(client, <rf216a_regmap_config);
450 if (IS_ERR(data->regmap))
451 return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
452 "regmap initialization failed\n");
453
454 i2c_set_clientdata(client, indio_dev);
455 data->client = client;
456 data->info = i2c_get_match_data(client);
457
458 mutex_init(&data->lock);
459
460 indio_dev->info = <rf216a_info;
461 indio_dev->name = "ltrf216a";
462 indio_dev->channels = ltrf216a_channels;
463 indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
464 indio_dev->modes = INDIO_DIRECT_MODE;
465
466 ret = pm_runtime_set_active(&client->dev);
467 if (ret)
468 return ret;
469
470 /* reset sensor, chip fails to respond to this, so ignore any errors */
471 ltrf216a_reset(indio_dev);
472
473 ret = regmap_reinit_cache(data->regmap, <rf216a_regmap_config);
474 if (ret)
475 return dev_err_probe(&client->dev, ret,
476 "failed to reinit regmap cache\n");
477
478 ret = ltrf216a_enable(indio_dev);
479 if (ret)
480 return ret;
481
482 ret = devm_add_action_or_reset(&client->dev, ltrf216a_cleanup,
483 indio_dev);
484 if (ret)
485 return ret;
486
487 ret = devm_pm_runtime_enable(&client->dev);
488 if (ret)
489 return dev_err_probe(&client->dev, ret,
490 "failed to enable runtime PM\n");
491
492 pm_runtime_set_autosuspend_delay(&client->dev, 1000);
493 pm_runtime_use_autosuspend(&client->dev);
494
495 data->int_time = 100000;
496 data->int_time_fac = 100;
497 data->als_gain_fac = 3;
498
499 return devm_iio_device_register(&client->dev, indio_dev);
500 }
501
ltrf216a_runtime_suspend(struct device * dev)502 static int ltrf216a_runtime_suspend(struct device *dev)
503 {
504 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
505 struct ltrf216a_data *data = iio_priv(indio_dev);
506 int ret;
507
508 ret = ltrf216a_disable(indio_dev);
509 if (ret)
510 return ret;
511
512 regcache_cache_only(data->regmap, true);
513
514 return 0;
515 }
516
ltrf216a_runtime_resume(struct device * dev)517 static int ltrf216a_runtime_resume(struct device *dev)
518 {
519 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
520 struct ltrf216a_data *data = iio_priv(indio_dev);
521 int ret;
522
523 regcache_cache_only(data->regmap, false);
524 regcache_mark_dirty(data->regmap);
525 ret = regcache_sync(data->regmap);
526 if (ret)
527 goto cache_only;
528
529 ret = ltrf216a_enable(indio_dev);
530 if (ret)
531 goto cache_only;
532
533 return 0;
534
535 cache_only:
536 regcache_cache_only(data->regmap, true);
537
538 return ret;
539 }
540
541 static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
542 ltrf216a_runtime_resume, NULL);
543
544 static const struct ltr_chip_info ltr308_chip_info = {
545 .has_clear_data = false,
546 .lux_multiplier = 60,
547 };
548
549 static const struct ltr_chip_info ltrf216a_chip_info = {
550 .has_clear_data = true,
551 .lux_multiplier = 45,
552 };
553
554 static const struct i2c_device_id ltrf216a_id[] = {
555 { "ltr308", .driver_data = (kernel_ulong_t)<r308_chip_info },
556 { "ltrf216a", .driver_data = (kernel_ulong_t)<rf216a_chip_info },
557 {}
558 };
559 MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
560
561 static const struct of_device_id ltrf216a_of_match[] = {
562 { .compatible = "liteon,ltr308", .data = <r308_chip_info },
563 { .compatible = "liteon,ltrf216a", .data = <rf216a_chip_info },
564 { .compatible = "ltr,ltrf216a", .data = <rf216a_chip_info },
565 {}
566 };
567 MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
568
569 static struct i2c_driver ltrf216a_driver = {
570 .driver = {
571 .name = "ltrf216a",
572 .pm = pm_ptr(<rf216a_pm_ops),
573 .of_match_table = ltrf216a_of_match,
574 },
575 .probe = ltrf216a_probe,
576 .id_table = ltrf216a_id,
577 };
578 module_i2c_driver(ltrf216a_driver);
579
580 MODULE_AUTHOR("Shreeya Patel <shreeya.patel@collabora.com>");
581 MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@liteon.com>");
582 MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
583 MODULE_LICENSE("GPL");
584